The devils is in the details, though. The obvious stuff (slurs etc.) is obvious.
But let’s take calling Kamala Harris “low IQ” as an example. My immediate response is that is a racist stereotype, TBH, BUT I have called Lt. Gov Robinson, for instance, a moron many times. Was I being racist?
I would like to try to have discussions first along the lines of “I hope you didn’t mean it this way, when you call Harris a “low IQ black woman” the reference to her race and gender as part of the insult seems to intentionally conflate your opinion (warranted or not) of her intelligence with her race and gender as support. I hope you can see how insulting that is to women and black people and harkens back to egregious stereotypes.”
I’m not naive enough to think that would be all that successful with some posters, but could change the tone with good faith posters.